Organic Dyes Containing Coplanar Dihexyl-Substituted Dithienosilole Groups for Efficient Dye-Sensitised Solar Cells

Scheme 1

Reagents and conditions: (i) 4-(diphenylamino) phenylboronic acid, palladium(II) acetate, cesium carbonate, toluene, reflux, 24 h, (ii) POCl₃, DMF, 90 °C, 24 h, and (iii) 2-cyanoacetic acid, piperidine, acetonitrile, reflux, 4 h.